9mm and .40S&W Ammo Question

[MikeNice]

Excuse me if this has been covered before.

Both 9mm and .40 S&W have a SAAMI pressure standard of 35,000. So, why is it that people say a 124gr bullet is recomended for a 9mm? Yet, people carry 150gr or larger .40S&W loads.

I know there must be something I just don't know that stops me from understanding this. If anybody can explain it to me feel free.

Also, what is the "recomended" size for a .40S&W bullet? I know a 155gr Gold Dot has been known to achieve 16" of penetration with .60" of expansion. Is this about the best overall performance size (size not bullet) for a .40 load?

I'm getting interested in .40S&W since I shot my cousin's yesterday. I don't think I would buy one any time soon. I am very interested in the round though. It feels more effective than 9mm to me. I know the differences are marginal at best. However, a weapon is supposed to be comforting not comfortable, right?

 

[rcmodel]

The advantage of the .40 S&W is it's ability to get good velocity with a heavier bullet then the 9mm.

It originally was designed for a 180 grain bullet at around 1,000 FPS.
Just about the same proven power as the 38-40 WCF some of the old time gunfighters used in Colt SAA's & Winchester rifles.

The early load for the 9mm Luger was a 115 or 124 grain, so that is what the guns were designed for.

Since then, lighter faster bullets have been developed for the .40 S&W, and many folks prefer them.

Heavier 147 grain bullets have came along for the 9mm, and many folks prefer them.

You pays your money and you makes your choices.

It depends on whether you subscribe to the big & slow theory of stopping power, vs the light & fast one.

The reason the .40 can toss heavier bullets then the 9mm at the same pressure is due to the bigger bore expansion ratio.

Just like a hot rod car engine, Bigger pistons = More horsepower.

rc

 

[speaksoftly]

 

[Shawn Dodson]

So, why is it that people say a 124gr bullet is recomended for a 9mm? Yet, people carry 150gr or larger .40S&W loads.

Bullet weight is not a valid comparison between cartridges of different caliber. Sectional density is the best measure in which to compare bullets. See - Sectional Density: Rule-of-thumb Guide for Estimating Terminal Performance at http://www.firearmstactical.com/tacticalbriefs/volume4/number1/toc.htm

For recommended loads, suggest you see Service Pistol Duty and Self-Defense Loads at http://www.m4carbine.net/showthread.php?t=19887

It's not the weight of the bullet that's important. Determine what kind of terminal performance you desire and then choose a load that best matches what you want the bullet to do.

 

[MikeNice]

Thank you Shawn.